That was the scene outside of a school in the northern Iraqi city of Mosul, where authorities said more than 100 people were killed Friday in fighting between security forces and al Qaeda-backed Sunni fighters.

The fighting follows news a day earlier that militants tried to take control of the city of Samarra to the south, violence spurred in part by an escalating conflict between Iraq's majority Shiite government and a Sunni minority who claim they are disenfranchised.

The violence has left hundreds dead in recent months, raising fears it could return Iraq to the level of violence in 2006 and 2007, when bodies littered the streets.

Nearly 500,000 people are estimated to have been displaced this year in fighting, primarily in the Sunni-dominated Anbar province, the United Nations refugee agency said Friday.

But that number is expected to climb, said Adrian Edwards, the spokesman for the U.N. High Commissioner on Refugees.

On Friday, Hares Hammadi al-Bajari was among dozens trying to flee the fighting in Mosul, where militants were attacking police stations and security checkpoints.

With a round-the-clock curfew in effect that banned people from driving, Bajari, a taxi driver, set out on foot with his family to try to make it to safety in the nearby Kurdish-controlled Duhok province.